问题如下图：
选项：
A. 
B. 
C. 
解释：
这个解释里的公式不是假设standard deviation same 吗？和B选项是否矛盾？
这如何理解B
NO.PZ2018070201000063问题如下Eunice, analyst from investment company, recently ma the following statements:Statement 1: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio increase;Statement 2: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio crease;Statement 3: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio remains the same.Whistatement is most correct?A.Statement 1.B.Statement 2.C.Statement 3.B is correct.the number of assets in the same weighting portfolio increases, the contribution of eainviasset's contribution to portfolio volatility creases. the number of assets in equally weighteportfolio increases, the contribution of co-movement measures between assets increases. The following equation for the varianof equally weighteportfolio illustrates these points:σρ2=σ¯2N+N-1NCOV¯=σ¯2N+N-1Nρσ¯2N越大，相关系数越小，分散化越好
NO.PZ2018070201000063问题如下 Eunice, analyst from investment company, recently ma the following statements:Statement 1: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio increase;Statement 2: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio crease;Statement 3: With the increase in the number of investment assets in the equweight portfolio, the contribution of the varianof eainviasset to the varianof portfolio remains the same.Whistatement is most correct?A.Statement 1.B.Statement 2.C.Statement 3.B is correct.the number of assets in the same weighting portfolio increases, the contribution of eainviasset's contribution to portfolio volatility creases. the number of assets in equally weighteportfolio increases, the contribution of co-movement measures between assets increases. The following equation for the varianof equally weighteportfolio illustrates these points:σρ2=σ¯2N+N-1NCOV¯=σ¯2N+N-1Nρσ¯2根据公式，随着数量的增加也就是可以理解成n增大，用极限的思想看，当N趋近于无限大时，1/N趋近于0，N-1/N趋近于1，也就是整个公式只会受COV的影响，题目给出的条件并不影响COV，为什么不是不变呢，我这个理解有什么问题吗
能下答案意思吗？不太明白和公式关系在哪
这道题不明白考的是哪个点？用答案里的多资产计算公式我觉得也和这道题说的单个资产对组合影响程度无关呢？
